Case C-450/12: Judgment of the Court (Tenth Chamber) of 12 December 2013 (request for a preliminary ruling from the Finanzgericht Düsseldorf — Germany) — HARK GmbH & Co KG Kamin- und Kachelofenbau v Hauptzollamt Duisburg (Common Customs Tariff — Tariff classification — Combined Nomenclature — Headings 7307 and 7321 — Stove pipe sets — Notions of ‘parts’ of stoves and ‘tube or pipe fittings’ )